Gelatin capsule with nu-alkyl amide, for aqueous vehicles



United States Patent 2,990,333 GELATIN CAPSULE WITH N-ALKYL AMIDE, FOR AQUEOUS VEHICLES Dean M. Graham, Summit, N.J., assignor to The Upjohn Company, Kalamazoo, Mich., a corporationof Delaware No Drawing. Filed June 29, 1959, Ser. No. 823,289 9 Claims. (Cl. 167-83) soft (plasticized) capsules and hard (unplasticized) capsules is well recognized. Soft gelatin capsules are onepiece sealed capsules enclosing the encapsulated components. They are made in various shapes and sizes. Hard gelatin capsules are usually composed of two parts, a cap and a body which are fitted together after the body has been filled with an appropriate component or components.

They are also made in a wide variety of sizes. Both soft capsules and hard capsules can enclose a wide variety of components. I The inherent mutual affim'ty of water and gelatin has resulted in serious difiiculties in the art of encapsulating components into either soft or hard capsules. Special precautions are required to keep the water content in said components and in any accompanying vehicle at the minimum. Otherwise the water exerts deleterious effects on the gelatin. In the case of soft capsules, water-immiscible oils are widely used as vehicles for the components to be encapsulated. In the case of hard capsules, the materials to be encapsulated must be dried to a minimum content of water prior to encapsulation. If special precautions to exclude water from the vehicle and the components are not followed carefully, both hard and soft capsules will break down during the encapsulation process. If the capsules do survive this process, storage after manufacture results in softening of the capsules, the appearance of small holes at the point of any contact between water and the gelatin shell of the capsule,

the gradual loss of the acceptable elegant character of the capsules and even loss of the encapsulated comin the use of soft capsules enclosing water-soluble components. Since oily vehicles are customarily used to carry the components, ready dispersion and solution of l the said components does not occur in aqueous media due to retarding of dispersion by the oil.

For example, after the oral ingestion of gelatin capsules for therapeutic purposes, the encapsulated components must normally become dissolved in the aqueous medium in the gastro-intestinal tract before absorption can take place. The components in oily vehicles must be leached away from the oil by the aqueous medium before the absorption can occur. Moreover, the use of oily vehicles in which many of the components to be encapsulated are insoluble greatly hampers the practical manufacture of filled gela- 'tin capsules. Many components must be encapsulated in larger capsules than would be necessary if a waterrniscible vehicle with no adverse elfects on gelatin were j available. It has been found also that some oily vehicles, particularly those carrying suspended components, are

very diificult to encapsulate because of high viscosity.

2,990,333 Patented June 27, 1961 Fee wherein R and R are members of'the class consisting of hydrogen anl alkyl radicals containing 1 to 2 carbon atoms, inclusive, and R is an alkyl radical containing 1 to 2 carbon atoms, inclusive. The vehicle is inert to gelatin, is water-miscible, and possesses superior solubilizing and dispersing action on a wide variety of components. Since the vehicle inhibits the action of water and hygroscopic substances on gelatin, both water and hydroscopic substances, in addition to other components, can be carried inthe vehicle.

- The present invention obviates the use of oily vehicles as' carriers for components to be encapsulated. Moreover, the capsule of the present invention provides ready dispersion of the encapsulated components upon contact of the capsule with an aqueous medium.

The inventive capsule encloses a vehicle containing a compound of the formula wherein R and R are members of the class consisting of hydrogen and alkyl radicals containing 1 to 2 carbon atoms, inclusive, and R is an alkyl radical containing 1 to 2 carbon atoms, inclusive.

The preferred amide is N,N-dimethylacetamide. Other amides of the class are, for example, N,N-dimethylformamide, N-N-diethylaceta-mide, N,N-dimethylpropionamide, N-methylacetamide and N-ethylformamide.

The said vehicle is practically inert to gelatin. Further, itinhibits the action of hygroscopic components or substantiall amounts of water on gelatin capsules. The afiinity of any Water present in the gelatin, in the diluted vehicle, or in the encapsulated components, for the ve hicle is much greater than for the capsule. Thus, the capsule is protected from solution in, or softening by the water, so that the capsule retains its shape during processing and its acceptable characteristics subsequent to manufacturing. Moreover, the Water-miscible nature of the vehicle furthers ready dispersion and solution in water of the encapsulated components.

The components are dissolved, suspended or emulsified in the vehicle by conventional means prior to encapsulation into the gelatin capsules. Encapsulation into the gelatin shells is carried out by means and methods known in the art. In the case of hard capsules, the known techniques for sealing the fitted body and cap can be utilized.

The dispersing and solubilizing properties of the vehicle of the invention are such that the vehicle can be used for the encapsulation of both liquid and solid components. The vehicle Will dissolve both water-soluble and water-insoluble components. For example, flavors, perfumes, essences, foaming agents, surfactants, cosmetics, food products, vitamins and medicinals can be encapsulated by utilizing said vehicle.

Hard gelatin capsules and soft gelatin capsules were exposed to the action of a vehicle containing N,N-di-- of the choline chloride.

These :data indicate that as much as thirty percent water does not adversely affect hard gelatin capsules, in the presence of the N,N-dimethylacetamide. In thecaseof .soft elastic capsules, as much as five percent water can be present without adverse effects.

The. following-examples set forth the best mode contemplated by'the inventor of carryingout his invention butare not to .be construed as limiting'the invention.

EXAMPLE '1 Soft gelatin capsules enclosing a vehicle containing. aqueous lemon juice concentrate are prepared as follows:

Mls. Aqueous lemon juice concentrate 50 N,N-'dimethylacetamide 950 EXAMPLE 2 Soft gelatin capsules enclosing'a vehicle containing choline chloride are prepared as follows:

Choline chloride gms.. 500 Purified water, U.S.P mls 40 .Nemethylacetamide, q.s. ad mls 1000 The choline chloride is mixed with the water and the mixture stirred into the amide. The wholeiis encapsulated by the usual techniques into 6.75 minim soft capsules. Each capsule encloses approximately 200 mg. The finished capsules .do not soften or leak. The capsules are used in liver disorders such as. fatty degeneration.

EXAMPLE 3 Soft gelatin capsules enclosing a vehicle containing novobiocin are prepared as follows:

Novobiocin gms 700 Purified water, U.S.P l1'l'1S N,N-dimethylacetamide, q.s. ad mls 1000 -A solution of the novobiocinin the water and amide is prepared and encapsulated by the usual techniques EXAMPLE 4 Soft gelatin capsules enclosing a vehicle containing an 'antiperspirant are prepared as'followsz Aluminum .chlorhydroxide complex -gms 20 Purified water, U.S.P mls 50 N,N-diethylformamide, q.s. .ad mls 1000 The aluminum chlorhydroxide is dissolved in the water.

The solution is made up to volume with the amide and "encapsulated by theusuail techniques into 16 minum'soft TABLE I 25 C. stability of gelatin capsules in vehicle containing N,N-dimethylacetamide Percent of Water in the Vehicle Hard Capsules 'Stable Stable..- Stable... Stable. Stable 'So1l;ens24 s. Soft Capsules Softens.-- Partially TDissclves- Dissblves- Dissolves. 96 hrs. 48 hrs.

' capsules provided with a tip. The finished capsules do EXAMPLE 5 Sealedsoft gelatin capsules enclosing a vehicle containing a vitamin mixture are prepared as follows:

Nicotinamide gms I 2 Vitamin B hy'drochloride mgs 50 D-calcium pantothenate mgs '700 VitamirbB; hydrochloride mgs "300 Vitamin C gms 5 Vitamin B mgs -2'50 -Folic arid mgs 25 Vitamin B -mg 0.250 Ethanol mgs 39 Vitamin A ;units 500,000 Vitamin D do 50,000

The wellmixed ingredients are encapsulated by the usual techniques into soft capsules. The sealed finished capsules do not soften Or leak. They are used in'the oral treatment of vitamin deficiencies.

N-methyl-N-ethylacetamide, q.s. -ad -minims EXAMPLE 6 7 Sealed hard gelatin capsules enclosing avehicle 'containing a detergent are prepared as follows:

Sodium lauryl sulfate gms 5 Purified water, U.S.P mls. 30 N,N-dimethylacetamide, q.s. ad mls 100 A solution of the sodium lauryl sulfatein the water is prepared and made up to volume with the acetamide. The whole is encapsulated by the usual techniques into hard gelatin capsules which are then-sealed. The finished capsules do not soften or leak. At the time of use the capsules are placed in water wherein rupture of thegelatin and dispersion of the capsule contents occur readily.

EXAMPLE 7 Sealed hard gelatin capsules enclosing a vehicle containing a vitamin mixture are'preparecl as follows:

The well mixed ingredients are encapsulated by the usual techniques into hard capsules. The sealed finished capsules do not soften or leak. They are used in the oral tme t Of Vitamin deficiencies.

EXAMPLE 8 Sealed hard gelatin capsules enclosing a vehicle containing a medicinal component are prepared as follows:

Novobiocin gms 700 Purified water, U.S.P. mls 100 N,N-dimethylacetamide, q.s. ad mls 1000 A dispersion of the novobiocin in the water is prepared and made up to volume with the acetarnide. Each sealed finished capsule contains 100 mgs. of the novobiocin. The finished capsules do not soften or leak. The capsules are used orally in the treatment of staphylococcic infections.

It is to be understood that the invention is not to be limited to the exact details of operation or exact compositions shown and described herein as obvious modifications and equivalents will be apparent to one skilled in the art, and the invention is therefore to be limited only by the scope of the appended claims.

What is claimed is:

l. A sealed gelatin capsule enclosing a liquid watermiscible vehicle containing a water-miscible amide of the formula wherein R and R are members of the class consisting of hydrogen and alkyl radicals containing 1 to 2 carbon atoms, inclusive, and R is an alkyl radical containing 1 to 2 carbon atoms, inclusive.

2. The capsule of claim 1 wherein the vehicle contains in addition a medicinal component.

3. The capsule of claim 1 wherein the vehicle contains in addition a vitamin component.

4. A sealed hard gelatin capsule enclosing a liquid water-miscible vehicle containing up to about 30 percent water based on the volume of said vehicle and a watermiscible amide of the formula wherein R and R are members of the class consisting of hydrogen and alkyl radicals containing 1 to 2 carbon atoms, inclusive, and R is an alkyl radical containing 1 to 2 carbon atoms, inclusive.

5. The capsule of claim 4 wherein the vehicle contains in addition a medicinal component.

6. The capsule of claim 4 wherein the vehicle contains in addition a vitamin component.

7. A sealed soft gelatin capsule enclosing a vehicle containing up to about 5 percent water based on the volume of said vehicle and a water-miscible amide of the formula 0 R R-( lN RI wherein R and R are members of the class consisting of hydrogen and alkyl radicals containing 1 to 2 carbon atoms, inclusive, and R is an alkyl radical containing 1 to 2 carbon atoms, inclusive.

8. The capsule of claim 7 wherein the vehicle contains in addition a medicinal component.

9. The capsule of claim 7 wherein the vehicle contains in addition a vitamin component.

References Cited in the file of this patent UNITED STATES PATENTS 2,667,268 Grifi'in Jan. 26, 1954- FOREIGN PATENTS 553,398 Canada Feb. 18, 1958 OTHER REFERENCES Chemistry and Industry article, Sept. 17, 1955, p. 1183. 

1. A SEALED GELATIN CAPSULE ENCLOSING A LIQUID WATERMISCIBLE VEHICLE CONTAINING A WATER-MISCIBLE AMIDE OF THE FORMULA 